SEARCH · PubMed Health

Results for “Multiple Classification Analysis”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 397 records · Page 22Linked to original sources

PubMed2006

Combined mitochondrial and nuclear sequences support the monophyly of forcipulatacean sea stars.

Previous molecular phylogenetic analyses of forcipulatacean sea stars (Echinodermata: Asteroidea) have reconstructed a non-monophyletic order Forcipulatida, provided that two or more forcipulate families are included. This result could mean that one or more assumptions of the reconstruction method was violated, or else the traditional classification could be erroneous. The present molecular phylogenetic analysis included 12 non-forcipulatacean and 39 forcipulatacean sea stars, with multiple representatives of all but one of the forcipulate families and/or subfamilies. Bayesian analysis of approximately 4.2kb of sequence data representing seven partitions (nuclear 18S rRNA and 28S rRNA, mitochondrial 12S rRNA, 16S rRNA, 5 tRNAs and cytochrome oxidase I with first and second codon positions analyzed separately from third codon positions) recovered a consensus tree with three well-supported clades (78%-100% bootstrap support) that corresponded at least approximately to traditional taxonomic ranks: the superorder Forcipulatacea (Forcipulatida + Brisingida) + Pteraster, the Brisingida/Brisingidae and Asteriidae + Rathbunaster + Pycnopodia. When a molecular clock was enforced, the partitioned Bayesian analysis recovered the traditional Forcipulatacea. Five of six genera represented by two or more species were monophyletic with 100% bootstrap support. Most of the traditional subfamilial and familial groupings within the Forcipulatida were either unresolved or non-monophyletic. The separate partitions differed considerably in estimates of model parameters, mainly between nuclear sequences (with high GC content, low rates of sequence substitution and high transition/transversion rate ratios) and mitochondrial sequences.

Animals↗

PubMed2003

Thymidine phosphorylase levels as a prognostic factor in renal cell carcinoma.

OBJECTIVE: To investigate the relationship between thymidine phosphorylase (TP), a vascular growth factor, and established prognostic factors for renal cell carcinoma (RCC), e.g. histological grade or Tumour-Node-Metastasis (TNM) classification. PATIENTS AND METHODS: TP levels were measured in RCC tissue (tumour TP) and in adjacent non-neoplastic kidney tissue (normal tissue TP), using a sandwich-type enzyme-linked immunosorbent assay. The 59 patients, diagnosed with organ-confined RCC before surgery and who had undergone radical nephrectomy, were divided into two groups according to their prognosis after surgery. Group 1 (nine patients) had a poor prognosis and group 2 (50) had no evidence of disease within a 65-month follow-up. The relationships among TP level, TNM classification, histological subtypes, V factor and prognosis, and of tumour TP to normal tissue TP levels were investigated. Multiple regression analysis was used to determine the importance of factors associated with increased TP levels. RESULTS: Normal tissue TP levels correlated with histological grade (r = 0.31, P < 0.01); in patients with venous invasion or with a poor prognosis, the levels were significantly higher than in those without (P < 0.05 and < 0.001, respectively). The normal tissue TP levels were also significantly higher in the non-clear cell than in the clear cell subtype. Multiple regression analysis showed that the independent factor associated with elevated normal tissue TP levels was histological grade (R2 = 0.189, P < 0.01). There was no correlation between tumour TP and other factors. CONCLUSION: Normal tissue TP levels in localized hypervascular RCC were associated with histological grade. These data suggest that normal tissue TP levels could be a prognostic factor.

Adult↗

PubMed1990

Attachment behavior at home and in the laboratory: Q-sort observations and strange situation classifications of one-year-olds.

This article reports Attachment Q-set data and Strange Situation classifications of 58 1-year-old middle-class infants. Security, dependency, and sociability were scored from Q-sort reports of home observations. The primary analyses involve comparisons between securely attached infants (Group B) and anxiously attached infants (Groups A and C combined). Additional analyses compare anxious-resistant with anxious-avoidant infants. Secure classification in the Strange Situation was associated with quality of secure-base behavior at home (i.e., higher Q-sort security scores) and with sociability, but not with dependency scores. Descriptive analyses of individual Q-set items support the secure-base interpretation of Strange Situation security classifications. Relations between home security scores and interactive behavior scores from the Strange Situation were also examined by multiple regression analysis.

Arousal↗

PubMed2006

Global warming and extinctions of endemic species from biodiversity hotspots.

Global warming is a key threat to biodiversity, but few researchers have assessed the magnitude of this threat at the global scale. We used major vegetation types (biomes) as proxies for natural habitats and, based on projected future biome distributions under doubled-CO2 climates, calculated changes in habitat areas and associated extinctions of endemic plant and vertebrate species in biodiversity hotspots. Because of numerous uncertainties in this approach, we undertook a sensitivity analysis of multiple factors that included (1) two global vegetation models, (2) different numbers of biome classes in our biome classification schemes, (3) different assumptions about whether species distributions were biome specific or not, and (4) different migration capabilities. Extinctions were calculated using both species-area and endemic-area relationships. In addition, average required migration rates were calculated for each hotspot assuming a doubled-CO2 climate in 100 years. Projected percent extinctions ranged from <1 to 43% of the endemic biota (average 11.6%), with biome specificity having the greatest influence on the estimates, followed by the global vegetation model and then by migration and biome classification assumptions. Bootstrap comparisons indicated that effects on hotpots as a group were not significantly different from effects on random same-biome collections of grid cells with respect to biome change or migration rates; in some scenarios, however, botspots exhibited relatively high biome change and low migration rates. Especially vulnerable hotspots were the Cape Floristic Region, Caribbean, Indo-Burma, Mediterranean Basin, Southwest Australia, and Tropical Andes, where plant extinctions per hotspot sometimes exceeded 2000 species. Under the assumption that projected habitat changes were attained in 100 years, estimated global-warming-induced rates of species extinctions in tropical hotspots in some cases exceeded those due to deforestation, supporting suggestions that global warming is one of the most serious threats to the planet's biodiversity.

Biodiversity↗

PubMedDate not supplied

A revised staging system for breast cancer.

The sixth edition of the American Joint Committee on Cancer (AJCC) staging system for invasive and in situ breast cancer has significant implications for the maximization of patient care. These evidence-based standards now reflect current standards of care and practice. Guidelines for a more uniform and accurate primary tumor analysis, including grade, size, and histologic classification are now provided, as well as standards for diagnosis and handling of microinvasion, multiple ipsilateral or contralateral carcinomas, and inflammatory carcinomas. The reporting of nodal metastasis has been refined and the characterization of metastatic disease has been revised. These revised guidelines should now be used for patient categorization, data gathering, and clinical categorization. National adaptation of these changes should greatly facilitate inter- and intrainstitutional standardization and data gathering.

Advisory Committees↗

PubMed2001

Prevalence and clinical significance of antikeratin antibodies and other serological markers in Lithuanian patients with rheumatoid arthritis.

OBJECTIVES: To assess the clinical value of several serological markers in Lithuanian patients with rheumatoid arthritis (RA) compared with control patients with rheumatic disease and age matched healthy controls. METHODS: Serum samples from 96 patients with RA of approximately 8 years' duration, 90 rheumatic disease controls, and 37 healthy subjects were tested. Antikeratin antibody (AKA), antineutrophil cytoplasmic antibody (ANCA), and antinuclear antibody (ANA) titres were estimated by indirect immunofluorescence (IIF) and serum samples positive for ANA and ANCA were further studied by enzyme linked immunosorbent assay (ELISA). IgA and IgM rheumatoid factors (RF) were measured by ELISA. RESULTS: A positive AKA test was highly specific for RA (diagnostic specificity 97%), being found in 44% of the patients. Although both RF tests had a higher sensitivity, they were less specific for RA. ANCA was detected in 33% of patients with RA but lacked diagnostic specificity. AKA and ANCA were associated with more erosive disease and the presence of extra-articular manifestations. Positivity for AKA, IgA RF, and ANCA was significantly associated with disease activity and worse functional capacity. However, in multiple regression analysis only positivity for AKA was significantly correlated with functional disability (p=0.0001), evaluated by the Steinbrocker functional classification, and no single marker had any relation with radiological damage. CONCLUSION: Although AKA showed the highest disease specificity, all serological markers studied except ANA exhibited interesting associations with important clinical and paraclinical parameters of RA.

Adult↗

PubMed1987

[Significance of primary radical surgery for survival following treatment of breast cancer. Problems of interpretation of treatment results of prospective, nonrandomized studies exemplified by the Southwest Germany Breast Cancer Study].

In a prospective non-randomised trial 1642 patients were included. After a mean time of 10 years a follow-up analysis was performed. The importance of the radicality of the primary operative therapy of breast cancer should be evaluated. The mean 5 years survival rate was 67.3%, the 10 year survival rate 51.6%. Tumor stage and age had a highly significant influence on the survival rate. Patients with simple mastectomy had a lower survival rate as patients with radical mastectomy. This apparent difference was caused by a different age distribution in the therapy groups. Accordingly the mean life deficiency was the lowest in the simple mastectomy group. In a multiple hazard statistical analysis tumor stage and age showed a highly significant influence on the survival rate. The intraoperative radicality classification showed a significant correlation to the prognoses of the patients. The operative therapy itself had no significant influence on the survival rate of the patients.

Adult↗

PubMed1986

A taxonomic analysis of multihospital systems.

Research to date on multihospital systems has proved largely uninformative, in part because similarities and differences among these organizations have not been addressed systematically. Through numeric classification, this article identifies populations of multihospital systems that share similar organizational attributes. Drawing on McKelvey's classification theory, 16 organizational characteristics of 160 multihospital systems are analyzed using a series of taxonomic techniques, including cluster analysis, multiple discriminant analysis, and analysis of coefficients of variation. Fifteen distinct subgroups of systems are identified and described, and their implications for organization research discussed.

Catholicism↗

PubMed1981

[Local and general immunity in diseases of the nervous system].

In normal condition, the nervous system has no local immunity, and general immunity is here very poor. However, in many neuro-immunological diseases, a local immunity appears, i.e.: a local synthesis of immunoglobulins. General immunity may be increased by transudation of blood components into CSF, either separately (inflammatory transudate) or simultaneously (meningitis) with this local synthesis. A mathematical formula is proposed is useful for some reasons: 1) evaluation of local immunity; 2) definition of CSF immunological patterns into 5 types and a neuro-immunological classification of neurological diseases; 3) research of the etiology in some nervous disease; 4) objective analysis of results of immunotherapy. Multiple sclerosis gives a good example of this 4 points of interest.

Capillaries↗

PubMed1997

Usher syndrome in the city of Birmingham--prevalence and clinical classification.

AIMS: To estimate the prevalence of Usher syndrome in the city of Birmingham, and to establish a database of patients who have been classified into different clinical subtypes essential for future gene mutation analysis. METHODS: Symptomatic cases of Usher syndrome (US) resident in the city of Birmingham in June 1994 were ascertained through multiple sources. Ophthalmic and audiological reassessment together with examination of medical records and patient questionnaires allowed classification of three subtypes, US 1, US 2, and US 3. In addition, family pedigrees were examined and blood was taken from index patients for DNA extraction. RESULTS: In the population aged over 15 years the prevalence was 6.2 per 100 000 population for all US subtypes. The prevalence for US 1 and US 2 was 5.3 per 100 000 population. This is greater than previously reported. In the age group 30-49 years the prevalence approached 1 in 10 000. Clinical classification found 33% US 1, 47% US 2, and 20% US 3. CONCLUSION: This higher prevalence rate and greater frequency of US 2 and US 3 may reflect a more complete ascertainment.

Adolescent↗

PubMed1995

Genetic heterogeneity of hepatitis C virus: quasispecies and genotypes.

Worldwide, HCV is a major etiologic agent of chronic hepatitis that may lead to the development of liver cirrhosis and hepatocellular carcinoma. Thus, significant morbidity and mortality is caused by HCV infection and effective control measures against the spread of this virus are needed. Originally, the extent of genetic heterogeneity of HCV was not fully appreciated. However, the breadth of the genetic heterogeneity of HCV is great, and this may have important implications in diagnosis, pathogenesis, treatment, and vaccine development. In an infected individual the HCV genome population circulates as a quasispecies distribution of closely related yet heterogeneous RNA sequences centered around one dominant sequence. The dominant sequence, as well as the consensus sequence, changes sequentially during the course of the infection. A hypervariable region (HVR1) within one of the envelope proteins of HCV (E2) evolves very rapidly. Patients infected with HCV mount a humoral immune response to epitopes of HVR1. However, sequential changes in the consensus sequence of HVR1 during infection result in the generation of variants that are not recognized by preexisting antibodies. This might represent a mechanism by which HCV evades host immune surveillance and establishes and maintains persistent infection. It will be important to determine whether HVR1 of HCV, as was found for the V3 loop of HIV, contains epitopes that elicit neutralizing antibodies against HCV. Furthermore, it will be important to determine whether the quasispecies nature of HCV helps the virus evade the cytotoxic T-cell response of the host. Analysis of complete or partial HCV genomic sequences revealed that HCV exists as multiple, distinct genotypes. A total of nine major genetic groups and at least 30 subgroups have been recognized. To evaluate the current classification of HCV genotypes, we performed phylogenetic analyses of complete and partial nucleotide sequences from isolates that represent all published variants of HCV. Analysis of complete HCV sequences, which represent three major genetic groups, supports the currently used genotype classification scheme. However, analysis of the partial genomic regions (ie, C, E1, and NS5b) of HCV isolates that represent all recognized variants of HCV demonstrates that the genetic relatedness among some of the genotypes was not equivalent in the different gene regions. Furthermore, the distinction among isolates, subtypes, and types of HCV was not always clear. This finding might reflect the shortcomings of analyzing only limited gene regions or may reflect the wide spectrum of genetic variation of HCV.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed2001

[Analysis of relationship between risk factors of malignant transformation of oral leukoplakia and the LSCP system].

OBJECTIVE: To explore the clinical significance of the LSCP (lesion size, site of lesion, clinical aspects, pathological aspects) classification and staging system through a comprehensive analysis of relationships between the risk factors of malignant transformation of 209 cases with oral leukoplakia and the LSCP classification and staging system. METHODS: Single factor Chi-square test was first performed to examine the associations between LSCP stages (I, II, III, IV) of oral leukoplakia and each of risk factors, including sex, site, size, numbers of lesion, alcohol and tobacco consumption, clinical classification and histopathological classification respectively, to select the most significant factors which influence the LSCP classification and staging. Then, the association of these selected factors with LSCP stages of oral leukoplakia (stage IV vs. I, II and III) was evaluated using multiple logistic regression analysis. RESULTS: Sex, site of lesions, clinical aspect and histopathological features of lesions were chosen as risk factors incorporated into the multiple logistic regression models. The results demonstrated that the risk of oral leukoplakia of the female patients classified as LSCP stage IV was 2.49 times as high as that of the male patients. The risk of lesions occurring in tongue and/or that floor of mouth was higher than that in other sites. Among the different clinical subtypes of lesions, the verrucous leukoplakia was the highest and 10.00 times as high as that of the homogeneous one. Among the different histopathological types, when hyperplasia and mild dysplasia were set as the basic level, the risk of severe dysplasia classified as LSCP stage IV was the highest and 499.55 times as high as the basic level, while that of moderate dysplasia was 276.48 times as high as the basic level. Pathological features with moderate and severe dysplasia were the most important contributory factors to the LSCP staging. CONCLUSIONS: The LSCP classification and staging system provides a comprehensive description of the features of oral leukoplakia, which is helpful in evaluating the overall risk of malignant transformation of oral lesion, and is valuable in clinical follow-up and developing the best treatment plan.

Adult↗

PubMed1985

Familial multiple trichodiscomas. A clinicopathologic study.

Three patients had hereditary multiple trichodiscomas of early onset and dominant inheritance. This report is an analysis of the histologic, histochemical, immunohistochemical, and electron microscopic findings in 27 trichodiscomas, the largest published series so far, to our knowledge. The tumors of perifollicular connective tissue are briefly reviewed and a classification is proposed. Hereditary multiple trichodiscomas are regarded as a new entity that should be distinguished from the syndrome recently described by Birt and associates that is characterized by autosomal dominant inherited fibrofolliculomas as the hallmark, associated with trichodiscomas and acrochordons.

Adult↗

PubMed1993

A latent trait finite mixture model for the analysis of rating agreement.

This article presents a latent distribution model for the analysis of agreement on dichotomous or ordered category ratings. The model includes parameters that characterize bias, category definitions, and measurement error for each rater or test. Parameter estimates can be used to evaluate rater performance and to improve classification or measurement with use of multiple ratings. A simple maximum likelihood estimation procedure is described. Two examples illustrate the approach. Although considered in the context of analyzing rater agreement, the model provides a general approach for mixture analysis using two or more ordered-caregory measures.

Data Interpretation, Statistical↗

PubMed2003

Genetic algorithms applied to multi-class prediction for the analysis of gene expression data.

MOTIVATION: An important challenge in the use of large-scale gene expression data for biological classification occurs when the expression dataset being analyzed involves multiple classes. Key issues that need to be addressed under such circumstances are the efficient selection of good predictive gene groups from datasets that are inherently 'noisy', and the development of new methodologies that can enhance the successful classification of these complex datasets. METHODS: We have applied genetic algorithms (GAs) to the problem of multi-class prediction. A GA-based gene selection scheme is described that automatically determines the members of a predictive gene group, as well as the optimal group size, that maximizes classification success using a maximum likelihood (MLHD) classification method. RESULTS: The GA/MLHD-based approach achieves higher classification accuracies than other published predictive methods on the same multi-class test dataset. It also permits substantial feature reduction in classifier genesets without compromising predictive accuracy. We propose that GA-based algorithms may represent a powerful new tool in the analysis and exploration of complex multi-class gene expression data. AVAILABILITY: Supplementary information, data sets and source codes are available at http://www.omniarray.com/bioinformatics/GA.

Algorithms↗

PubMed2002

Validation using sensitivity and target transform factor analyses of neural network models for classifying bacteria from mass spectra.

Temperature constrained cascade correlation networks (TCCCNs) are computational neural networks that configure their own architecture, train rapidly, and give reproducible prediction results. TCCCN classification models were built using the Latin-partition method for five classes of pathogenic bacteria. Neural networks are problematic in that the relationships among the inputs (i.e., mass spectra) and the outputs (i.e., the bacterial identities) are not apparent. In this study, neural network models were constructed that successfully classified the targeted bacteria and the classification model was validated using sensitivity and target transformation factor analysis (TTFA). Without validation of the classification model, it is impossible to ascertain whether the bacteria are classified by peaks in the mass spectrum that have no causal relationships with the bacteria, but instead randomly correlate with the bacterial classes. Multiple single output network models did not offer any benefits when compared to single network models that had multiple outputs. A multiple output TCCCN model achieved classification accuracies of 96 +/- 2% and exhibited improved performance over multiple single output TCCCN models. Chemical ionization mass spectra were obtained from in situ thermal hydrolysis methylation of freeze-dried bacteria. Mass spectral peaks that pertain to the neural network classification model of the pathogenic bacterial classes were obtained by sensitivity analysis. A significant number of mass spectral peaks that had high sensitivity corresponded to known biomarkers, which is the first time that the significant peaks used by a neural network model to classify mass spectra have been divulged. Furthermore, TTFA furnishes a useful visual target as to which peaks in the mass spectrum correlate with the bacterial identities.

Bacteria↗

PubMed1997

Hepatic resection for hepatocellular carcinoma.

BACKGROUND: The significance of pTNM staging of hepatocellular carcinoma (HCC) as a prognostic factor after hepatic resection was evaluated. PATIENTS AND METHODS: The prognoses were analyzed in 262 patients treated with hepatic resection for HCC. RESULTS: As a whole, the pTNM stages correlated well with the survival rates. The survival rates of stage I and II patients were significantly higher than those of stages III and IV. However, there was no significant difference in survivals between stage I and II, and between stage III and IV-A. The survival rates of the patients treated with segmentectomy or lobectomy in stages I and II were significantly higher than those with subsegmentectomy or smaller resection. Multivariate analysis revealed that tumor size greater than 2 cm, multiple gross tumors, surgical margin less than 1 cm, and Child C classification were independently significant factors of poor survival. CONCLUSIONS: The results of hepatic resection for HCC should be stratified by pTNM staging and by Child classification of hepatic function before comparison.

Adult↗

PubMed2002

An index to quantify normality of gait in young children.

Gait patterns are often described by recording the changes in angular rotation of such joints as the hip, knee and ankle, during a complete cycle. Each joint exhibits distinctive behavior throughout the gait cycle, and abnormal gait can be described by measuring departure from a typical (mean) joint rotation curve. Standard techniques for observation of gait patterns produce large sets of data. Data reduction is achieved in this work by locating primary directions of variation from mean behavior. Variation from the mean can then be summarized with a one-dimensional statistic, thought of as a squared distance from the population mean. Percentiles of this one-dimensional index can be calculated, enabling classification of a child as normal, unusual or abnormal. A key feature of this analysis is that it is applied across multiple joint angle curves and their derivatives, thus providing a measure that takes account of the interactions between the curves as well as their individual characteristics. A data base of 348 gait cycles, collected from normal children, aged 3-7, were analyzed. Data on each child were stored in a 36-dimensional vector. Most information on patterns of variation among normal children can be stored in a smaller 11-dimensional vector, which can be used for diagnostic purposes. Performance of the one-dimensional index of gait is demonstrated on data from very young children, and on children, up to age 7, who were born prematurely.

Ankle Joint↗